DL Control Resources Sets and RACH Procedure during Initial Access

1. A user equipment device (UE), comprising: at least one antenna; at least one radio, wherein the at least one radio is configured to perform cellular communication using at least one radio access technology (RAT); one or more processors coupled to the at least one radio, wherein the one or more processors and the at least one radio are configured to perform communications; wherein the one or more processors are configured to cause the UE to: receive a configuration for a control resource set (CORESET) for a Type0 physical downlink control channel (PDCCH) search space set based on supporting at least 96 physical resource blocks (PRBs) for one or more of 120 kilohertz (kHz), 480 kHz, or 960 kHz sub-carrier spacing (SCS); receive, in a synchronization signal block (SSB) burst window (SSBBW), one or more SSB transmissions and at least one of a Type0 PDCCH search space set in CORESET #0 or a remaining minimum system information (RMSI) that is paired with an SSB transmission in the same SSBBW based on the configuration; and determine, based on a configuration index included in a higher later parameter, positions of random access channel (RACH) occasion (RO) slots associated with a high frequency SCS within a reference physical RACH (PRACH) slot window associated with a reference SCS, wherein the positions of ROs are located in a last slot associated with the high SCS of the PRACH slot window.

2. The UE of claim 1, wherein the configuration for a CORESET is specified by a data structure that includes one or more indexes, wherein each index of the one or more indexes specifies an SSB and CORESET multiplexing pattern, a number of PRBs for the CORESET, a number of symbols for the CORESET, and an offset between a smallest Resource Block (RB) index of the CORESET and a smallest RB of a corresponding SSB.

3. The UE of claim 1, wherein the resource block offset is applied for all SCSs or a subset of SCSs, and wherein the resource block offset is specified as at least one of [0, 1, 2, 4] or [0, 2].

4. The UE of claim 1, wherein the one or more processors are further configured to cause the UE to: monitor a Type0 physical downlink control channel (PDCCH) search space set in at least one of the CORESET #0 or RMSI slot that is paired with an SSB index of the one or more SSB transmissions within the SSBBW.

5. The UE of claim 1, wherein the one or more SSB transmissions are received in an SSB slot in the SSBBW with a first SCS; and wherein the Type0 PDCCH search space set for RMSI scheduling is monitored in a CORESETO/RMSI slot in the SSBBW with a second SCS.

6. The UE of claim 5, wherein there is a one-to-one association between SSBs transmitted in the SSB slot in a SSBBW and the Type0 PDCCH search space set for the UE to monitor in the CORESETO/RMSI slot in the SSBBW.

7. The UE of claim 5, wherein the SSB slots include a first M consecutive slots of the SSBBW with a first SCS and the CORESETO/RMSI slots include a subsequent N consecutive slots of the SSBBW with a second SCS, and wherein values of <M, N>pairs are specified for one or more combinations of first SCSs and second SCSs, and wherein the first SCS is smaller than the second SCS.

8. The UE of claim 1, wherein the one or more processors are further configured to cause the UE to: receive, via a downlink control indicator (DCI) format 1_0 that schedules random access channel (RACH) response (RAR) transmissions, a segment index of a corresponding RACH occasion (RO), wherein the segment index is based, at least in part, on a sub-carrier spacing (SCS), wherein the segment index is a field of the DCI format 1_0 that schedules RAR transmissions, wherein the segment index is indicated via least significant bits (LSBs) of a sequence frame number (SNF) information element (IE) of the DCI Format 1_0 that schedules RAR transmissions or via a first part and a second part, wherein the first part is included in a payload of DCI Format 1_0 with CRC scrambled by RA-RNTI, wherein the second part is conveyed by selecting a scrambling sequence to scramble CRC bits of DCI Format 1_0, and wherein the first part indicates an index associated with the scrambling sequence; and determine a random access (RA) radio network temporary identifier (RNTI) based on a physical random access channel (PRACH) transmission window being divided into a number of slot sub-groups, wherein the number of slot sub-groups is based on the SCS of the RO and determines the segment index, and wherein the RA-RNTI associated with an RO is determined based on a reference SCS that is larger than the SCS of the RO.

9. An apparatus, comprising: a memory; and at least one processor in communication with the memory and configured to: receive, in a synchronization signal block (SSB) burst window (SSBBW), one or more SSB transmissions and at least one of a random-access control resource set (CORESET) #0 or a remaining minimum system information (RMSI); monitor a Type0 physical downlink control channel (PDCCH) search space set in at least one of the CORESET #0 or RMSI paired with an SSB index of the one or more SSB transmissions in the same SSBBW; and determine, based on a configuration index included in a higher later parameter, positions of random access channel (RACH) occasion (RO) slots associated with a high frequency SCS within a reference physical RACH (PRACH) slot window associated with a reference SCS, wherein the positions of ROs are located in a last slot associated with the high SCS of the PRACH slot window.

10. The apparatus of claim 9, wherein the one or more SSB transmissions are received in an SSB slot in a SSBBW with a first SCS; and wherein the Type0 PDCCH search space set in CORESET #0 for RMSI scheduling is monitored in a CORESETO/RMSI slot in the SSBBW with a second SCS.

11. The apparatus of claim 10, wherein there is a one-to-one association between SSBs transmitted in the SSB slot in a SSBBW and the Type0 PDCCH search space set for a UE to monitor in the CORESETO/RMSI slot in the SSBBW.

12. The apparatus of claim 10, wherein the SSB slots include a first M consecutive slots of the SSBBW with a first SCS and the CORESETO/RMSI includes a subsequent N consecutive slots of the SSBBW with a second SCS.

13. The apparatus of claim 9, wherein the at least one processor is configured to: determine a distribution of ROs based on a total number of time domain ROs in the PRACH slot of the reference SCS, wherein the SCS is one of a 480 kHz SCS or a 960 kHz SCS that is larger than the reference SCS of PRACH slot.

14. A method, comprising: receiving a configuration for a control resource set (CORESET) for a Type0 physical downlink control channel (PDCCH) search space set based on supporting at least 96 physical resource blocks (PRBs) for one or more of 120 kilohertz (kHz), 480 kHz, or 960 kHz sub-carrier spacing (SCS); receiving, in a synchronization signal block (SSB) burst window (SSBBW), one or more SSB transmissions and at least one of a Type0 PDCCH search space set in CORESET #0 or a remaining minimum system information (RMSI) that is paired with an SSB transmission in the same SSBBW based on the configuration; and determining, based on a configuration index included in a higher later parameter, positions of random access channel (RACH) occasion (RO) slots associated with a high frequency SCS within a reference physical RACH (PRACH) slot window associated with a reference SCS, wherein the positions of ROs are located in a last slot associated with the high SCS of the PRACH slot window.

15. The method of claim 14, wherein the configuration for a CORESET is specified by a data structure that includes one or more indexes, wherein each index of the one or more indexes specifies an SSB and CORESET multiplexing pattern, a number of PRBs for the CORESET, a number of symbols for the CORESET, and an offset between a smallest Resource Block (RB) index of the CORESET and a smallest RB of a corresponding SSB.

16. The method of claim 14, wherein the resource block offset is applied for all SCSs or a subset of SCSs, and wherein the resource block offset is specified as at least one of [0, 1, 2, 4] or [0, 2].

17. The method of claim 14, further comprising: monitoring a Type0 physical downlink control channel (PDCCH) search space set in at least one of the CORESET #0 or RMSI slot that is paired with an SSB index of the one or more SSB transmissions within the SSBBW.

18. The method of claim 14, wherein the one or more SSB transmissions are received in an SSB slot in the SSBBW with a first SCS; and wherein the Type0 PDCCH search space set for RMSI scheduling is monitored in a CORESETO/RMSI slot in the SSBBW with a second SCS.

19. The method of claim 18, wherein there is a one-to-one association between SSBs transmitted in the SSB slot in a SSBBW and the Type0 PDCCH search space set to monitor in the CORESETO/RMSI slot in the SSBBW.

20. The method of claim 18, wherein the SSB slots include a first M consecutive slots of the SSBBW with a first SCS and the CORESETO/RMSI slots include a subsequent N consecutive slots of the SSBBW with a second SCS, and wherein values of <M, N>pairs are specified for one or more combinations of first SCSs and second SCSs, and wherein the first SCS is smaller than the second SCS.